Preparation

Make blackberry jam:

Mash blackberries with sugar using a potato masher or fork in a 3- to 4-quart heavy saucepan. Cook over moderately high heat, stirring occasionally, until slightly thickened, about 7 minutes. Stir in lemon juice, then force through a sieve into a bowl, discarding seeds. Chill jam, its surface covered with wax paper, until softly set, at least 15 minutes.

Make cake:

Put oven racks in upper and lower thirds of oven and preheat oven to 350°F.

Generously butter cake pans and put a rounded 1/3 cup nut mixture into each pan. Tilt each pan to coat bottom and sides with nut mixture, letting excess remain in bottom of pan.

Sift together flour, baking soda, and salt in a bowl. Stir together buttermilk, orange zest and juice, and vanilla in a small bowl.

Beat together butter (2 sticks), brown sugar, and remaining 1/2 cup granulated sugar in bowl of mixer with paddle attachment at medium-high speed until pale and fluffy, about 5 minutes. Add eggs, 1 at a time, beating well after each addition. Reduce speed to low and add flour and buttermilk mixtures alternately in batches, beginning and ending with flour mixture and mixing just until batter is smooth. Divide batter among cake pans.

Bake, switching position of pans halfway through baking, until a wooden pick or skewer inserted in centers of cakes comes out clean and edges begin to pull away from sides of pans, about 30 minutes. Cool in pans on racks 15 minutes, then run a thin knife around edge of each pan. Invert racks over pans, then flip cakes onto racks to cool completely, about 1 hour.

Make buttercream:

Put egg whites and salt in cleaned bowl of mixer.

Bring brown sugar and water to a boil in a 1-quart heavy saucepan over moderately high heat, stirring until sugar is dissolved, and washing down side of pan occasionally with a pastry brush dipped in water. When sugar syrup reaches a boil, start beating egg whites with whisk attachment at medium-high speed until whites just hold soft peaks. (Do not beat again until sugar syrup is ready.)

Continue to beat meringue, scraping down bowl once or twice with a rubber spatula, until meringue is cool to the touch, about 10 minutes. (It is important that meringue is properly cooled before proceeding.)

With mixer at medium speed, gradually add butter to meringue 1 piece at a time, beating well after each addition and until incorporated. (If meringue is too warm and buttercream looks soupy after some of butter is added, briefly chill bottom of bowl in a large bowl filled with ice water for a few seconds before continuing to beat in remaining butter.) Continue beating until buttercream is smooth. (Mixture may look curdled before all of butter is added, but will come back together as beating continues.) Add vanilla and beat 1 minute more.

Assemble cake:

Put 1 cake layer, nut side up, on a cake plate or platter. Spread 1 1/2 cups buttercream on top but not side, then top with another cake layer, nut side up. Spread top with 1 1/2 cups buttercream, then top with remaining layer, nut side up.

Gently toss whole blackberries with jam in a large bowl. Arrange blackberries, stemmed sides down, on top of cake.

Cooks' notes:
Jam keeps, chilled in an airtight container, 2 weeks. Bring to room temperature before using.
Cake layers can be baked 2 days ahead and kept, wrapped in plastic, at room temperature.
Buttercream can be made ahead and chilled, covered, 1 week or frozen 1 month. Bring to room temperature (do not use a microwave) and beat with electric mixer until smooth before using.
Assembled cake keeps, loosely covered, at room temperature 1 day.

SELECT LATEST REVIEWS

The best cake I have ever made! Fantastic result never lacking in flavour. Make sure to make this cake in season so as not to lose on the main flavour of the blackberries. Will definetley be making this recipe with rasberries or peaches just for a twist!

A Cook from Toronto, On / 03.01.12

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other people mentioned that the frosting was really fatty so instead of 3 stiks i used 2 and it still came out pretty bad in my opinion. my fiance likes it though. and the cake was pretty good, nothing special though. i might try the cake with a different frosting

mindxxxslaughter from san francisco, ca / 03.03.10

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This recipe sounded so good that I made it for an important family birthday. I followed the recipe exactly and it turned out fine - not hitches. BUT it was so not worth the work. The flavors weren't all that special or different. Big dissappointment - won't make it again.

A Cook from Toledo, Ohio / 11.20.09

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This cake was somewhat dry, the flavors could have been interesting together, but totally not worth the fuss. I won't make it again.

A Cook from Toledo, Ohio / 08.11.09

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Made this for my mom's birthday a few years back and she said it was the best cake she's had... which is saying a lot! I still dream about it.

A Cook from los angeles, ca / 05.23.09

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I made this for
friends and used
peaches instead of
blackberries. It
was fantastic, and
everyone raved. One
friend said it was
in her top five of
favorite cakes, and
it wasn't even made
with chocolate.
(She is a certified
chocoholic.) If
you're using
peaches, cut down on
the sugar and add a
bit more cornstarch.

A Cook from east bay / 08.09.08

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This cake was visually stunning, but to me, it just tasted like butter and sugar, no real flavor. Standard good wedding cake taste. I'm all about flavor so I would not make this again.

puuwai from kauai / 06.03.08

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This is a heavy dense cake. I made a cranberry jam (straiined) instead of blackberries- and it was great. I spread thin layers of both the cranberry jam and the buttercream frosting between each cake layer.

laugh55 from Bloomfield Hills, MI / 05.12.08

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Spectacular. I made
this cake for a good
friend's birthday,
and everyone raved.
I think it's one of
the best cakes I've
ever tasted. I made
the recipe as is and
wouldn't change a
thing. The tartness
of the berries is a
perfect foil to the
richness of the
buttercream. I will
make this again and
again and again...

mercury613 from San Francisco, CA / 01.01.08

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I made this cake for my brother's birthday party and it was a hit. A few people told me that the frosting was very rich (as someone else here has mentioned, it is a bit fatty - something I would fix the next time I make it), but that was the only negative comment. The cakes were delicious. I used hazelnuts instead of walnuts, and i frosted the sides and top of the cake because there was SO much frosting. I think a half-recipe would have sufficed! Also, I did not make the jam but rather used store-bought blackberry jam and spread a little of that between each layer. I simply topped the frosted cake with fresh blackberries. Overall, minor changes to an excellent recipe!